The present invention relates to a suspension control apparatus/method for a vehicle.
Vehicles equipped with navigation apparatus have been conventionally provided with a suspension control apparatus which can execute a suspension control corresponding to road condition data received from the navigation apparatus. With such suspension control apparatus, for example, when a curve is detected based on road data such as a profile of the road ahead, an adjustment of the suspension strength is calculated based on the shape of the detected curve, steering and vehicle speed. See, for example, Japanese Patent Publication No. 5-345509.
Further, there has been proposed control of suspension strength based on a data base with data indicating roughness of the road. See, for example, Japanese Patent Publication No. 2000-322695. In this case, learning is executed by acquiring data for vertical acceleration as input from the suspension. Based on the acquired vertical acceleration data roughness of the road is determined and recorded in the data base. In other words, results of actual control of the suspension are compared with an estimated control, and the data base is corrected based on the comparison.
However, the above-mentioned suspension control apparatus, which executes suspension control based on data for the shape of the road received from the navigation apparatus, differentiates only between a paved road and an unpaved road, and the actual road surface profile including its irregularities is not considered. Further, with respect to the vehicle state, only the vehicle speed and the steering are considered. Accordingly, the advance setting of control of the suspension on the rough road may cause the driver to feel a sense of discomfort.
Further, in the case of executing learning, since the learning is not of the road surface profile but, rather, with regard to the location where a swing is felt, the learning sometime disregards vehicle parameters such as the vehicle speed and vehicle weight. In the case that the advance control of the suspension for a rough road is based on learning in the manner mentioned above, the driver feels a sense of discomfort.